This invention relates to a pressure gauge or pressure indicator having axially-operating internal members with visual indication.
Recently, due to the strong development in the marketing of certain fire-extinguishers, made on a commercial scale and designed to be installed on motor-vehicles and motor-boats, the manufacturers of such fire extinguishers strongly need a pressure gauge which is very simple, easily and economically obtainable on a commercial scale, and which can, therefore, be mounted on said extinguishers as an indicating means for checking the conditions of the charge. For this purpose, several types of simplified pressure gauges have been developed, all based on the use of a Bourdon tubular spring member with various transmission members and a movable indicating pointer or sector and respective dial. Nevertheless, despite of any simplification in the mechanism of these components, the cost thereof has not been reduced appreciably. Practically, therefore, this problem has not yet been solved, and this led to researches to develop a pressure gauge wherein the traditional components have been omitted and which is, therefore, more simple and economical.
The article according to the invention is the output of said researches and has extremely attractive characteristics.